In many sectors and notably aeronautics, the gain in weight is a major issue for improving the energy efficiency of the equipment.
The gain in weight is generally in contradiction with the other major issue of these sectors: mechanical strength.
In the example of an aircraft, many elements consist of composite materials associating low weight and increased mechanical strength.
Presently, floors or wall covering components in majority consist of composite panels comprising a central honeycomb core (or “nida-core”), and of two “skins” attached on either side of the honeycomb core. These skins comprise one or several layers of identical or different materials.
In particular, the composite panels presently used are formed with a stack of layers consisting of an aluminium ⅛ nida-core (3.2 mm mesh) of specific gravity 98 kg/m3 from Hexcel© or from Alcore Brigantine© and of an external skin of the poly(p-phenyleneterephthalamide) 20914 type (better known under its trade name of Kevlar®), woven according to a weave of the 4H satin type, and pre-impregnated with an epoxy resin 1454 from Hexcel©.
Draping is made manually with the possibility of covering the whole of the decorative plies of fabric, without any impact on the mechanical strength of the panels.
Attachment inserts are provided for attaching these panels on supports in the position of use. The inserts presently used are in stainless steel adhesively bonded by means of a structural adhesive or of the densification resin type with a diameter of 30 mm.
The edges of each panel are covered with a specific bordering resin of density 0.68.
Present panels have the advantage of being very resistant to peeling, i.e. to the separation of different layers. They are therefore floors resistant to wear and to friction generated by the passing of the users.
Nevertheless, present panels have many drawbacks. Their mass always remains too high relatively to the increasingly restrictive construction requirements as regards aircraft.
Further, they have a more substantial deflection under a local load than a panel according to the embodiments comprising carbon skins. This phenomenon comes from the fact that the Kevlar® fiber used for the skins is a more elastic fiber than carbon fiber.
Finally, they have low resistance to impact and require being covered with a protective layer, for example carpeting.